PHOENIX -- After two days watching the Jodi Arias trial, a body language expert says the 32-year-old confessed killer is putting on an act for the court, but also appears very nervous.

"Jodi, in my opinion, is a young lady who can put on an act at will," Renate Mousseux told 3TV. "She knows exactly how to charm people."

During testimony, Arias frequently covers her face, or leans on her hand.

"It shows she's uneasy, and uncomfortable," Mousseux said, "Each time you touch your face, you display discomfort. You don't want to be in that situation."

Arias broke down as a prosecutor detailed the crime scene, in which Arias' boyfriend, Travis Alexander, was found shot and stabbed nearly 30 times.

However, Mousseux called Arias' emotions 'phony.'

"She wipes her nose like she'd be crying. However, her facial expression is not like crying. There are no real tears. Just like in other cases with women like Casey Anthony. They cry and make gestures, but their facial expressions don't lead to real tears," said Mousseux.

Arias has changed her initial claims of innocence, and now admits she killed her boyfriend in 2008, but claims it was in self-defense.